Conveyer boom hoisting system



Dec. 30, 1952 R, N, BENNETT 2,623,629

CONVEYER Boom HoIsTING SYSTEM Filed May 19. 1949 3 Sheets-Sheet l INVENTOR ROBERT N. BENNETT lob ' lNvENToR R BERT N. BENNETT 15# 5 Sheets-Sheet 2 R. N. BENNETT CONVEYER BOOM HOISTING SYSTEM Dec. 30, 1952 Filed May 19, 1949 TH l? INVENTOR 5 Sheets-Sheet 3 ROBERT N. BENNETT WIM# 'w R. N. BENNETT CONVEYER BOOM HOISTING SYSTEM Dec. 30, 1952 Flled May 19, 1949 Patented Dec. 30, 1952 UNITED STATES ATENT OFFICE CONVEYER BOOM HOISTIN G SYSTEM Application May 19,1949, serial No. 94,182

7 Claims. 1

This invention relates to conveyors for coal and the like and more particularly to means for raising and lowering a conveyor boom pivotally or otherwise movably mounted on a fixed or transportable supporting structure.

Coal conveyors are provided in some cases with manually operated winding drums and cables for the purpose of raising and lowering their conveyor booms. Such manual operation requires considerable time and effort and is especially undesirable in the case of large conveyors. Various means of powering the hoisting means have been tried, particularly means powered by the same motor which drives the drag chains along the boom, For example, it has been known to mount a hydraulic ram and cylinder to extend transversely between the boom and the supporting structure in order to control the position of the boom by the direct action of the ram. This arrangement, however, has the disadvantage that the ram is located where it is exposed to the elements and either a very long ram has to be used or else the ram has to be located so close to the pivotal mounting of the boom that the portion of the boom extending beyond the ram is subject to severe bending stresses. Other hoisting mechanisms have been tried but have not been satisfactory, generally because of a large number of parts projecting on the outside of the conveyor Which get in the way of the operator of the conveyor, which increase the hazard of injury to men around the conveyor, and which are exposed to damage by rough usage and the weather.

My apparatus for hoisting a conveyor boom uses a hydraulic cylinder and ram, a cable connected to the ram, and a drum on which the cable is wound, or a plurality of these elements, all mounted within the conveyor boom and out of the way of damage to or injury caused by these elements. The drum is preferably mounted near the end of the cylinder opposite to the ram in order to provide a compact arrangement, and the shaft carrying the drum projects outside of the boom to actuate the means which are directly connected to the boom to hoist it on the supporting structure. In my hoisting system this means comprises a drum or drums mounted on the shaft outside of the boom and a cable or cables wound thereon and extending between the boom and the supporting structure. In order to balance the hoisting mechanism and to enable a smaller diameter and therefore more iiexible cable to be used, pairs of inner and outer drums and corresponding additional cables are preferably used, the inner drums being mounted on opposite sides of the axis of the hydraulic cylinder and ram and the outer drums being mounted on the respective ends of the shaft projecting on opposite sides of the boom. The cables on the outside drums are wound oppositely to the cables on the inside drums so that when the ram moves `outwardly from the cylinder the inner drums will unwind and cause the outer drums to wind in their cables, thereby lifting the boom, and when the fluid pressure in the cylinder is released the weight of the boom will draw the cables from the outer drums and cause'the inner drums to wind up the cable connected to the ram, thereby retracting the ram.

I provide a hydraulic system which checks the outflow from the hydraulic cylinder in order to control the rate at which the boom is lowered. andv I provide a safety locking means to hold the boom in a raised position. My system is compact and protected from the elements and rough usage, has a minimum of protruding parts, and also is particularly useful for economy in manufacturing conveyors. It is desirable in the manufacture of conveyors to provide booms of varying lengths but to use as many standard subassemblies as possible. The power hoist mechanisms heretofore in use are not readily adjustable for the changing loads and shifts in center of gravity resulting from mounting booms of different lengths on a series of conveyors. My new hoisting system, on the other hand, is readily adjusted for diiierent lengths of booms by changing the length of cable or cables on the outer drum or drums and, if necessary, changing the sizes of the drums or the relative diameters of the inner and outer drums. Also, in order to increase the power of my hoisting system, a ram and cylinder of a larger diameter or a plurality of parallel rams and cylinders may conveniently be substituted without requiring materially greater space within the boom.

Further novel features and advantages of the apparatus of my invention will become apparent from the following detailed description and in the accompanying drawings. I have shown in the drawings for purposes of illustration only the following preferred embodiment of my invention, in which:

Figure 1 is a side elevation of a conveyor for coal and the like incorporating my invention;

Figure 2 is a transverse sectional view of the conveyor bed taken on the line II-II in Figure 1, Figure 3 is a partial bottom plan view of the conveyor bed shown in Figure l; l

Figure 4 is a partial longitudinal section take generally in the form of a recumbent U with its.y

ends extending on either side of the boom and with the tips of the ends carrying a: cross-pin l2 on which one end of the boom ispivotally mount-v ed. A shoe member I3 is alsopivotally mounted; on the pin I2 and rests on the ground while the? conveyor is in operation. A pair. of .spacedtripod supports i4 are rigidly mounted on the undercarriage Il and extend above and on either; side. of the boom I9 in order to provide a support for the hoisting.means herein-after described. Apair of Wheels: l5 are mounted: on, either side of theondercarriage beneath the-supports h3 in order to facilitate moving theconveyor from place to place.

vThe-boom Ithas a. conveyor bed l5 extending alongitslength with a series of paddles l1 carried. 'by` a; pair of drag chains I9 for pushing coal along the length of the conveyor bed. At the other' end of the boom I0 opposite to its pivotal mounting-a coal screenerv I9 is mounted with an outlet.20 for thescreened coal and an outlet 2l for thescreenings. The drag chains i8 are driven through .azchain drive 22 connected to amotor. 25 mounted on the boom I9. The motor shown in the drawings is--a gasoline-powered motor but any convenient form of motor may be used, such as anfelectr-icmotor. The drive shaft 23 oi' the motor-is connected through a friction clutch 24 controlledrbyfalever25 to a shafti whichinturnis conneetedto the chain drive 22 through a jaw .clutch21 controlled by a lever 28. In the case of .an electric. motor. the. clutch 2l!v may beomitted.

A. hydraulic ram 29.5and cylinder 39 supply the power. for hoistingtheboom I9 on the supports I4 and` in turn are supplied with power by a hydraulicpump 3l. driven by a chain drive 32 from the shaft 26. The pump 3| is supplied through a conduit33 with. hydraulic fluid from a tank 34. A` conduit 35,-connectsthe outlet of the pump 3| to-avalvef36; The `valve 36 is a spool-type threewayl valve of. known. constructionv and connects the :0nduit35v witha return flow conduit 31 and witha-v conduit 'whichis` connected to a port 3,9 opening into the interior. of thecylnder 39. The spool. within thevalve 3.6 is connected to a lever 49.- andisslidableby the lever 49 to three positions; In-.the rst or driving position thev valve 36=blocksthe conduit 31 and connects the conduit 35.tothe conduit 39 so that the-pump-3l supplies iiuid under pressure to the cylinder` 39, thereby supplying power to the ram 29 to hoist the boom I0. In thesecond or neutral position the valve connects theconduit 35 to the conduit 31 so that thepump- 3l` merely circulates iiuid through itself toand fromthe tank 34 and blocks the conduit 38 so that' the'ram is held in an extended positionY and the boom I0 is thereby held in a raised position. In the third or release position the valve.3.3-connectsiboth'the conduit 35 landi-the conduit '381 tothe return ow conduit 31 so that the pump` circulates iluid through itself to and romthe tank .3.4"and'atthesame time fluid in the cylinder 30y is free to lflow through the conduits 38 and 31 back to the tank`34, therebypermittinggthe-ram 29fto be. retracted withingthe cylina. wl

der 3U during the lowering of the boom l0 as hereinafter described. The pump 3| and the valve 38 are shown in Figures 1 and 5 in the form of an integral unit 38-a (such as a Vickers Power Pack), but separate pump and valve units may be used if so desired. In order to release the ram 29 in the event of an excessive load a relief valve d] is. connected tothe conduitfi` and theipressure relief outlet of the valveili'l is connected through a conduit 92 to the return fiow conduit 31. In addition, a valve 43 is connected to the conduit 38 to control the. rate of backow through the conyduitili whenthe valve 36 is in its release position. The valve i3 is a known form o1 valve in which.ballach'eckvalve i5 is connected in parallel withl a restricted. orice 45 controlled by an adjustable needle 65. The check valve i4 is arranged to open when fluid is being pumped to- Wardrthecylinder 39 and to close when iluid 1s returning from the cylinder 39. The result of this arrangement is that the `valve does not impede flow through conduit while the pumpBl is iilling the cylinder 35. but whenthevalve 36.is in its. released position therest-ricted oriiice 4.5 and the needle it inthe valve 43. are effectiveto reduce therate of backflow from the cylinder- 30 toany-desired rate so .that the boom will be lowiered ata controlled rate of speed.

The ram. 29 and cylinder 35 are mounted withinthe boom i9 and extend generally alongcthe axis ofV the boombeneaththe. conveyor bed It. Thefbaseor closedy end'of vthe cylinder 30V is .Welded to 'a plate 41T whichinturniswelded to a channeled crossfmember d3 fastened to thebed I6 and to oppositeside plates Iii-aand lil-b of the boom Il?. The port 39 extends from the interior of one end of. the cylinder. 39- through the.4 plate 41 and memberi toconnect with. the conduit 33, and theother end-.oi the.v cylinder 39, is held by a U- bar 49bo1ted. to. arnember 5,9. secured to a boom cross-member. 5l. Theram 29r nts snugly and slidably within thecylincler 30andoneend of the .ramprotrudes from the cylinder land. isbolted to a member 52;secured to. a cable 53 by bolted U- bars 53. rlhe two ends of the cable53 extend backv toward the base of the cylinder on either side of the cylinder and are wound in the same direction around and-are dead-ended on `a pair of drums 55 mounted on Yand keyed to a shaft 5 6. The shaft 56 extends through and is journaled in thesideplates IU-a andl -b andis .alsorotatably mounted inabearing 51 located between the drums55andrigdly secured to the cross-member` 56.. Theend of the shaft 55 extendingthrough thesideplate IEB-a mounts andis vkeyed to a-drum 59. The other end of the shaft 53 extending through the side plate. I9-b mounts and is keyed toa drum 59.; A rigid ratchet wheel in the form of a ring is rigidly fastened tothe drum 59 on the side of the drum next to the side plate lil-b. A handle 5| is pivotally mounted lat its lower end on a stud 62 secured to the sideof the plate lil-b and an integral tooth projects from the handle'l and is engageablewith the ratchet wheel. 69 to prevent'the ratchet wheel from revolving in a clockwise-direction as shown in Fig.- ure l (counter-clockwise as shown in Figure 4).. The upperl end of the handle. BI may be grasped by the operator-oi the conveyor to lift thetooth 63 out of engagement with the ratchet wheelbut in the absence of sucht control the handle 6l is biased byA gravity to swing against the ratchet wheel 69 so thatV the tooth 63 chatters on the ratchet WheelA while the drums 58 and 59 are-rotating in a` counter-clockwise. direction as shownl 5 in Figure 1 and so that the tooth 63 locks the said ratchet wheel and drums against rotation in the other direction.

A cable 64 is dead-ended on the drum 58 and a cable E5 is dead-ended on the drum 59, cables 64 and 65 being wound in the same direction around the drums 58 and 59 but in a direction opposite to the winding of the ends of the cable 53 around the drums 55. On each of the supports l 4 an idler pulley 66 is mounted above and on opposite sides of the conveyor boom I0. The cables 64 and 65 extend closely along opposite sides of the boom l from beneath the respective drums 53 and 59, over the respective pulleys 66, and down to respective fastening points adjacent opposite lower edges of the boom l0, where these cables are deadended. Equivalent cable rigging arrangements include mounting the pulleys 66 on the boom I0 and dead-ending the cables on the supports M.

The operation of the hoisting mechanism is as follows, assuming that at the start the clutches 24 and 21 are disengaged and the boom I0 is in its lowered position as shown in dotted lines in Figure l. After the motor is started clutch 24 is operated to connect shaft 23 to drive shaft 26 and thereby, through the chain drive 32, to drive pump 3|. Valve 36 through lever til is then operated to connect conduits 35 and 38 so that the ram 29 is forced to move outwardly from the cylinder 36. This unwinds the ends of cable 53 from the drums 55 within the boom l0 and thereby causes the drums 55, the shaft 55 and the outside drums 58 and 59 to rotate in a counter-clockwise direction as shown in Figure 1 (clockwise as shown in Figure 4), with the tooth 33 chattering on the ratchet wheel 6U. The cables 64 and 65 are thus wound up on the drums 53 and 59 and the ends of these cables fastened to the boom l0 are drawn up toward the pulleys 66 mounted on the supports I4. This action may be continued until the boom is raised to any desired position, such as that shown in full lines in Figure 1. The valve 36 is then changed by the lever 40 to its neutral position, in which the valveV 36 blocks the conduit 38 so that the ram is locked in its extended position (unless an excessive load causes the relief valve 4l to open and bypass uid from the cylinder 3l! through conduit 42). The ratchet wheel 6U acts as a secondary holding mechanism in the event of failure of the hydraulic system. The conveyor being positioned for operation, the motor is connected to drive the drag chains I8 by disengaging the friction clutch 24, engaging the jaw clutch 27, and re-engaging the friction clutch 24. The drag-chain drive and the hoistingr mechanism can be operated at the same time if desired but it is not necessary to impose both of these loads on the motor at the same time. The motor is needed to drive the hoisting system only while `the boom I0 is being raised and at all other times the motor may be clutched and declutched or may be started and stopped for the purpose of driving and stopping the dragchains I8, without regard to the hoisting system. When the boom lo is to be lowered the tooth 63 is lifted and held away from the ratchet wheel 6i! by means of the lever 6I during the period of the lowering operation and the lever 40 is operated to move the valve 36 to its release position. The ram 29 is thus freed from fluid pressure within the cylinder 3|) and the weight of the boom l0 lowers the boom and unwinds the cables from the drums B and 59, thereby rotating these drums, the shaft 56 and the inner drums 55 in a clockwise direction as shown in Figure 1 (counter-clockwise as shown in Figure 4). Such rotation winds the cable 53 on the inner drums 55 and draws the ram 29 back within the cylinder 3U. The rate of downward movement of the boom IB is controlled by the valve 43 and the lowering operation may be halted or reversed by changing the setting of the valve 36, which thus affords a very convenient control. The valve 36 is spring-loaded to return the valve to neutral position so that the hydraulic system will become locked if the man operating the conveyor releases the lever 40 during the raising or lowering of the boom. Moreover, the man operating the conveyor has to hold the lever El away from the ratchet Wheel 60 during the lowering operation so that if he loses control of the machine for any reason, such as falling off his platform on the undercarriage l l, the ratchet tooth 63 will swing against the wheel B0 and will prevent the boom from swinging down and causing injury to itself or to some other equipment or person. In the event of failure of the hydraulic system the ratchet arrangement is self-operating, or may be operated by the man holding the lever 6|, to lock the boom lll against downward movement.

While I have shown and described a present preferred embodiment of my invention it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced without departing from the spirit of the invention and within the scope oi the following claims.

I claim:

1. Boom hoisting mechanism for a conveyor for coal and the like which has a supporting structure and an elongated conveyor boom pivotally mounted on the supporting structure, said mechanism comprising a hydraulic cylinder mounted within the boom and extending in the direction of the length of the boom, means; to supply fluid under pressure to the cylinder', a ram extending from the cylinder, a shaft extending transversely through the boom, driving connections between the ram and a portion of the shaft within the boom so that relative movement of the ram in the cylinder causes the shaft to rotate, and means extending between the boom and the supporting structure and operable to hoist the boom on the supporting structure, said hoisting means being connected to be driven by a portion of the shaft projecting outside of the boom, whereby the shaft is rotatable by the ram to hoist the boom.

2. Boom hoisting mechanism for a conveyor for coal and the like which has a supporting structure and an elongated conveyor boom plvotally mounted on the supporting structure, said mechanism comprising a hydraulic cylinder mounted within the boom and extending in the direction of the length of the boom, means to supply iiuid under pressure to the cylinder, a ram extending from one end of the cylinder, a shaft rotatably mounted adjacent the other end of the cylinder and extending transversely through the boom, a drum mounted on and nxed to the shaft within the boom, a flexible tension member connecting the ram and drum, and hoisting means extending between the boom and the supporting structure and connected'to be driven by a portion of the shaft projecting outside of the boom, whereby the ram rotates the shaft to drive the boom hoisting means.

3. Boom hoisting mechanism for a conveyor for coal and the like" which hasv a supporting structure, anl elongated boom pivotally mounted on the supporting structure, conveying means extending along the boom, and a motor connected todrive said conveying means, said hoisting mechanism comprising a hydraulic pump, driving means connecting the motor and pump, a hydraulic cylinder mounted Within the boom, a conduit connecting the pump and cylinder, a ram extending from the cylinder, a shaft rotatably mounted on and extending through and outside or the boom, driving means mounted Within the boom and connecting the ram and shaft so that movement ofthe ram rotates the shaft, and means connected to a projection of the shaft outside of the boom and drivable by the shaft to hoist the boom on the supporting structure.

4. Boom hoisting mechanism for a conveyor for coal and the like which has a supporting structure, an elongated boom pivotally mounted on the supporting structure, conveying means mounted on and extending along the boom, and a -motor connected to drive said conveying means, said hoisting mechanism comprising a hydraulic pump, driving means connecting said motor and pump, a hydraulic cylinder mounted within the boom, a conduit connesting said pump and cylinder, a ram extending from the cylinder, a shaft rotatably mounted on and extending through and outside of the boom, a drum mounted on and fixed to the shaft inside of the boom, a flexible tension member connecting the ram and the drum, a drum mounted on and ixed to the shaft outside of the boom, and a exible tension member extending from the outside drum to the boom and to the supporting structure, said flexible members being wound in opposite directions around said drums so that one member will be wound on its drum While the other member is unWound from the other` drum.

5. Boom hoisting mechanism for a conveyor forcoal and the like which has a supporting structure, an elongated boom pivotally mounted on the supporting structure, conveying means mounted on and extending along the boom, and motor mounted on the boom and connected to drive said conveying means, said hoistingi mechanism comprising a hydraulic pump, driving means connecting' said motor and pump, a hydraulic cylinder mounted within the boom, a conduit connecting saidv pump and cylinder, a ram extending from the cylinder in the direction of the length ofV the boom, a shaft rotatably mounted on and extending through and outside of the boom, a drum mounted on and xed to the shaft inside of the boom, a flexible tension member connecting the ram and the drum, a drum mounted on and fixed to the shaft outside of the boom, and a lexible tension member deadended' onthe outside drum and asociated With the boom and the supporting structure to lift the boom on the supporting structure, the said flexible members lbeing wound in opposite directions around said drums and said outside drum being of greater diameter than said inside drum; whereby a short stroke of the. ramcausesV a larger movement of the flexible tension memberwhich lifts the boom on the supporting-structure.

6. Boom hoisting mechanism for a conveyor for coal and the like which has a supporting structure, an elongated boom pivotally mounted on the supporting structure, coal conveying means mounted on and extending along the, boom, and a motor mounted on the boom and connected to drive said coal conveying means,

said hoisting mechanism comprising a hydraulicV pump, driving means connecting said motor and pump, a hydraulic cylinder mounted Within the boom, a conduit connecting saidpump and cylinder, a ram extending from the cylinder. in the direction of the length of the boom, a shaft rotatably mounted on and extending throughand outside of the boom, said shaft being disposed 'ransversely of the axis of the ram adjacent the opposite end of the cylinder from the ram, a pair of drums mounted on and fixed to the shaft inside of the boom, said inside drums being mounted on opposite sides of the axis of the ram, a flexible tension member dead-ended on each of said inside drums and engaged by the ram, a pair of drums each mounted on and fixed to opposite ends of the shaft projecting outside of the boom, idler pulleys mounted on opposite sides of the boom, and flexible tension members each secured at one end to one of said outside drums and secured at the other end to said supporting structure above the boom, the intermediate portion of each of the last-mentioned fiexible members passing over one of said idler pulleys;

7. A conveyor for coal and the like comprising a supporting structure, an elongated boom pivotally mounted on the supporting structure, conveying means mounted on and extending along the boom, a motor mounted on the boom and connected to drive said conveying means, a hydraulic pump driven by the motor, a hydraulic cylinder rigidly secured to the boom, a conduit connecting said pump and cylinder, a ram extending from the cylinder in the direction of the length of the boom, means extending between' the boom and the supporting structure and operable to hoist the boom on the supporting structure, and driving connections between the ram and said means operable to hoist the boom.

ROBERT N. BENNETT.

REEERENCES CITED The following references are of record in theV file of this patent:

UNITED STATES PATENTS Number Name Date 856,759 Beebe et al June 11, 1907 1,090,670 Zimmerman Mar. 17, 1914 1,784,872 Hartman Dec. 16, 1930 2,116,905 Mercier et al May 10, 1938 2,354,336 Sloane July 25, 1944 2,427,461 Johnson Sept. 16, 1947 

